TEOS-O3 oxidizing film depositing system and process for supplying ozone (O3) thereto

ABSTRACT

A method and apparatus for controlling the amount of ozone concentration in the layers of a film depositing system and the multi-layered structure produced thereby, whereby the concentration of ozone in each layer gradually changes from a low ozone concentration in the first deposited layer to a high ozone concentration in the last deposited layer.

This application is a divisional of copending application Ser. No.08/773,175, filed on Dec. 27, 1996, the entire contents of which arehereby incorporated by reference.

FIELD OF THE INVENTION

The present invention relates to a TEOS-O₃ oxidizing film depositingsystem. More specifically, the present invention relates to a TEOS-O₃(alkoxysilane) oxidizing film depositing system suitable for improvinglower layer dependence and evenness in TEOS-O₃ oxidizing film depositionand the process for supplying ozone thereto.

BACKGROUND OF THE INVENTION

In general, the lower layer dependence of a TEOS (tetraethylortho-silicate)-O₃ oxidizing film is influenced by the content of ozone(O₃). To improve the lower layer dependence, the ozone concentrationshould be suitably adjusted, i.e. a plurality of TEOS-O₃ layers shouldbe formed with different ozone concentrations. In other words, it isintended to improve the lower layer dependence and evenness by adjustingthe ozone concentration of the TEOS-O₃ whereby the layer deposited firsthas the lowest O₃ concentration which is gradually increased in thelater deposited TEOS-O₃ layers. The "lower layer dependence" of TEOS-O₃film means that the TEOS-O₃ film has differences in thicknesses and inquality (density) according to the characteristics of the layers formedon its lower portion. For example, when an oxidation film is formed onthe substrate and a poly pattern is formed on a predetermined portion ofthe oxidation film, if TEOS-O₃ is formed on both the oxidation film andthe poly pattern, the thickness and the quality (density) of the TEOS-O₃film on the oxidation film are different from that of the TEOS-O₃ filmformed on the poly pattern. In other words, the TEOS-O₃ film ishydrophilic and so is the oxidation film, whereas the poly pattern ishydrophobic. Thus, the TEOS-O₃ film has a better characteristic ofdeposition over the poly pattern rather than over the oxidation film.

A conventional TEOS-O₃ oxidizing film depositing system is describedwith reference to FIG. 1.

FIG. 1 is a block diagram of a conventional TEOS-O₃ oxidizing filmdepositing system.

As can be shown in FIG. 1, the conventional TEOS-O₃ oxidizing filmdepositing system comprises an ozone generating zone 2 which generatesozone from oxygen introduced through a suitable adjusting Mass FlowController (MFC) zone 1 and a Mass Flow Controller (MFC) zone 2 whichcontrols the amplitude of the flow. A chamber 3 is provided where thedepositing of the TEOS-O₃ oxidizing film on a wafer takes place byintroducing oxygen and ozone generated in the ozone generating zone 2 aswell as a silicon source through opening 3b into the chamber.

The chamber comprises a first inlet opening 3b for introducing thesilicon source and depositing the TEOS-O₃ oxidizing film on a wafersubstrate 3a. A second inlet opening 3c is provided for introducingozone having a finally adjusted concentration into the chamber.Dispersion head 3d disperses the silicon source and ozone introducedthrough the first and second inlet openings 3b and 3c on the wafer 3a. Aheater 3e is operatively associated with the wafer 3a.

The TEOS-O₃ oxidizing film depositing system suitably adjusts the outputof the ozone concentration from the ozone generating zone (2) to form aTEOS-O₃ oxidizing film layer. The ozone is formed, for example, by theUV radiation of air or oxygen and its concentration can be varied byadjusting the amount of current applied to the UV lamp. The ozoneconcentration of the oxidizing film layer which is first deposited onthe wafer 3a is reduced if the flow of oxygen from the Mass FlowController zone 1 increases. Upon gradually reducing the oxygen inflow,the ozone concentration increases accordingly.

However, the conventional TEOS-O₃ oxidizing film depositing systemdescribed above has the following disadvantages.

First, a long time is required for the ozone concentration to reach astabilized state, and this shortens the life span of the UV lamp.

Second, if the TEOS-O₃ oxidizing film is deposited by using very lowozone concentration in order to remove lower layer dependence due tohigh ozone concentration, the evenness will deteriorate.

SUMMARY OF THE INVENTION

The object of the present invention is to overcome the above mentionedproblems and to provide a TEOS-O₃ depositing system which is suitablefor enhancing the precise supply and control of ozone concentration andevenness in the film deposition.

Other objects and further scope of applicability of the presentinvention will become apparent from the detailed description givenhereinafter. However, it should be understood that the detaileddescription and specific examples, while indicating preferredembodiments of the invention, are given by way of illustration only,since various changes and modifications within the spirit and scope ofthe invention will become apparent to those skilled in the art from thisdetailed description.

In order to achieve the above object, the TEOS-O₃ oxidizing filmdepositing system according to the present invention comprises a chamberfor accommodating a wafer; a first control zone which controls theamount of O₂ being introduced in order to adjust the O₃ concentration;an ozone generating zone for generating O₃ and supplying O₂ +O₃generated in accordance with the amount of O₂ introduced in the firstcontrol zone; and a second control zone which controls the amount of gasfor adjusting the ozone concentration introduced to control the O₃concentration in the O₂ +O₃ mixture supplied to the chamber from theozone generating zone. The process for supplying O₃ to the TEOS-O₃oxidizing film depositing system thus comprises the steps of preparingO₂ +O₃ from O₂ as a source; adding a gas for controlling the O₃concentration in the O₂ +O₃ mixture, and supplying the O₂ +O₃ having theO₃ concentration controlled by said gas to the TEOS-O₃ oxidizing filmdepositing system.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will become more fully understood from thedetailed description given hereinbelow and the accompanying drawingswhich are given by way of illustration only, and thus, are notlimitative of the present invention, and wherein:

FIG. 1 is a block diagram of a conventional TEOS-O₃ oxidizing filmdepositing system;

FIG. 2 is a block diagram of a TEOS-O₃ oxidizing film depositing systemaccording to the present invention; and

FIG. 3 is a sectional view showing a multi-layer TEOS-O₃ film accordingto the present invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENT

The TEOS-O₃ oxidizing film depositing system according to-the presentinvention, and the process for supplying O₃ thereto are described byreferring to the figures attached hereto.

FIG. 2 is a block diagram of a TEOS-O₃ oxidizing film depositing systemaccording to the present invention. The system comprises a first MFC 11,ozone generating zone 12, a second MFC 13, and a chamber 14.

The chamber comprises a first inlet opening 14b for introducing thesilicon source in order to deposit the TEOS-O₃ oxidizing film on a wafer14a; a second inlet opening 14c for introducing ozone in a finallyadjusted concentration; a dispersion head 14d which disperses thesilicon source and ozone introduced through the first and second inletopenings 14b, 14c on the wafer 14a; and a heater 14e.

The first MFC 11 controls the amount of oxygen introduced into the ozonegenerating zone 12, thereby providing a first adjustment in the ozoneconcentration.

The ozone generating zone 12 generates O₂ +O₃ for introduction to thechamber 14, depending upon the amount of oxygen introduced from thecontrol of the first MFC.

The second MFC 13 provides a second control for controlling the amountof a gas for adjusting the ozone concentration which is secondlyintroduced to more precisely adjust the ozone concentration in O₂ +O₃stream supplied from the ozone generating zone 12 to the chamber 14.

Thus, the first and second gas for adjusting the ozone concentrationvaries the ozone concentration as the amount of the gas graduallyincreases, to form a multi-layer TEOS-O₃ oxidizing film layer.

The gas introduced from the second MFC 13 is selected from the groupconsisting of oxygen, oxygen+ozone, and other gases which are notreactive with the silicon source.

The amount of finally adjusted O₃ to the amount of O₂ +O₃ supplied tothe chamber 14 utilizing the controls of the first and the second MassFlow Controllers 11, 13 is 0.5 to 7% by weight, and the amount of ozoneper unit volume (O₃ /m³) is 5 to 120 g.

The process for supplying ozone to the present TEOS-O₃ oxidizing filmdepositing system having the construction described above is set forthhereinbelow.

FIG. 3 is a sectional view showing the TEOS-O₃ oxidizing multi-layerfilm formed in accordance with the present invention.

As illustrated in FIG. 3, the multi-layer film is first formed by aTEOS-O₃ oxidizing film layer having a low ozone concentration followedby TEOS-O₃ oxidizing film layers having gradually increasing ozoneconcentrations, whereby the evenness of the TEOS-O₃ oxidizing film isenhanced. In other words, the first MFC 11 primarily controls the amountof oxygen introduced into the ozone generating zone for adjusting theozone concentration. Thus, the ozone generating zone 12 generates acorresponding amount of ozone depending on the amount of oxygenintroduced to the ozone generating zone from the first MFC 11.

Then, the second MFC 13 is used for a more precise adjustment of theozone concentration. The second MFC 13 introduces a gas for furthercontrolling and adjusting the ozone concentration in ozone+oxygen streamflowing from the ozone generating zone 12 to the chamber 14.

As stated above, the gas used as a second control is selected from thegroup consisting of oxygen, oxygen+ozone, ozone, and other gases whichare not reactive with the silicon source.

Thus, a TEOS-O₃ oxidizing film layer having more precise ozoneconcentrations can be formed in a multi-layer configuration by adjustingthe ozone concentration two times to gradually alter the final ozoneconcentration.

The amount of finally adjusted O₃ to the amount of O₂ +O₃ supplied intothe chamber 14 utilizing the control of the first and the second MFC 11,13 is 0.5 to 7% by weight, and the amount of ozone per unit volume (O₃/m³) is 5 to 120 g.

The TEOS-O₃ oxidizing film depositing system and the process forsupplying ozone thereto according to the present invention havefollowing effects.

First of all, the ozone concentration can be precisely controlledbecause the concentration thereof is controlled at least twice.

Secondly, the formation of a TEOS-O₃ oxidizing film having multi-layersenables the manufacture of the product with improved evenness.

Thirdly, the life span of the ozone generating zone is prolonged.

The invention being thus described, it will be obvious that the same maybe varied in many ways. Such variations are not to be regarded as adeparture from the spirit and scope of the invention, and all suchmodifications as would be obvious to one skilled in the art are intendedto be included within the scope of the following claims.

What is claimed is:
 1. A system for controlling the oxidation of a filmon a substrate which comprises:a chamber for accommodating a substrate,an ozone generating zone, first control means for introducing oxygen ina controlled amount into the ozone generating zone and recovering astream of ozone and oxygen therefrom, a second control means forintroducing a gas in a controlled amount into the ozone and oxygenstream to further adjust the concentration of the ozone therein, whereinthe gas provided for the second control means is selected from the groupconsisting of oxygen, ozone, and oxygen-ozone, with or without a gaswhich does not react with the oxygen source, and means for introducingthe final ozone-containing stream into the chamber.
 2. The system ofclaim 1, wherein means are provided for introducing a silicon sourceinto the chamber.
 3. The system of claim 2, wherein the chamber containsa distribution zone and said means for introducing the finalozone-containing stream into the chamber, and said means for introducingthe silicon source into the chamber communicate with said distributionzone.
 4. The system of claim 3, wherein a wafer provided with a heateris disposed in the chamber.
 5. The system of claim 1, wherein the firstcontrol means and the second control means are first and second massflow controllers, respectively.
 6. The system of claim 1, wherein theamount of finally adjusted ozone to the amount of oxygen+ozone suppliedto the chamber is 0.5 to 7% by weight, and the amount of ozone per unitvolume (O₃ /m³) is 5 to 120 g.